1. Field of the Invention
This invention relates to a semiconductor strain detector for use as a pressure sensor, for example, and more particularly to temperature compensation of a zero-point and/or sensitivity of the semiconductor strain detector.
2. Description of the Related Art
Semiconductor strain detectors utilizing semiconductor strain gauges have hitherto been used as apparatus for converting an amount of mechanical displacement to an electrical signal. Such apparatus is exemplified by a semiconductor pressure sensor.
Such a conventional semiconductor pressure sensor is composed of a pressure detector formed on a silicon single crystal and utilizing a semiconductor strain gauge. The sensor measures a pressure in terms of the resistance change of the semiconductor strain gauge which is caused by a pressure change.
In this conventional pressure sensor, partly because compact size and high precision can be realized by .mu.m-order micro-machining technology, and partly because mass production can be easily achieved by a semiconductor manufacturing apparatus, sharp reduction in production cost can be expected and, therefore, the practical use of the pressure sensors is on the progress in the fields of automobile and household appliances.
However, since a semiconductor is temperature dependent in itself, it is necessary to apply a temperature compensation to a semiconductor pressure sensor. In general, the temperature characteristics of a semiconductor pressure sensor can be classified into (1) a temperature characteristic independent of impressed pressure, namely, a zero-point temperature characteristic, and (2) a temperature characteristic dependent on pressure, namely, a sensitivity-temperature characteristic.
The zero-point temperature characteristic and the sensitivity-temperature characteristic in the conventional semiconductor pressure sensor will now be separately described in detail.